SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment reporting
Number of reportable segments | segment			3
Revenue
Revenue	$ 109,098	$ 107,721	$ 220,004	$ 211,021
Depreciation and amortization	21,991	21,549	44,509	42,267
Non-cash stock-based compensation	1,561	2,028	2,721	3,334
Operating income (loss)	7,024	2,754	14,324	4,869
Segment Assets
Cash, Cash equivalents, and Investments	125,083		125,083		$ 161,703
Total current assets	244,190		244,190		228,723
Fixed assets, net	587,857		587,857		605,581
Goodwill	60,691		60,691		60,691
Total assets	1,111,605		1,111,605		1,130,726
Total current liabilities	118,432		118,432		119,669
Total debt	84,624		84,624		86,426
Capital Expenditures
Capital expenditures			31,965	35,396
Communication services
Revenue
Revenue	106,240	105,019	214,145	205,633
Mobility
Revenue
Revenue	21,429	23,807	43,968	46,896
Fixed
Revenue
Revenue	61,504	58,576	124,818	116,661
Carrier services
Revenue
Revenue	22,753	22,298	44,468	41,399
Other
Revenue
Revenue	554	338	891	677
Other
Revenue
Revenue	2,858	2,702	5,859	5,388
Renewable Energy
Revenue
Revenue	874	1,448	2,196	2,938
Managed Services
Revenue
Revenue	1,984	1,254	3,663	2,450
Corporate and Other
Revenue
Depreciation and amortization	1,656	1,754	3,359	3,244
Non-cash stock-based compensation	1,402	2,017	2,599	3,313
Operating income (loss)	(8,799)	(9,991)	(16,623)	(18,045)
Segment Assets
Cash, Cash equivalents, and Investments	12,380		12,380		55,284
Total current assets	46,880		46,880		55,485
Fixed assets, net	20,183		20,183		21,453
Total assets	162,112		162,112		184,419
Total current liabilities	21,647		21,647		14,375
Capital Expenditures
Capital expenditures			1,519	4,519
International Telecom | Operating segments
Revenue
Revenue	80,064	79,859	162,349	160,176
Depreciation and amortization	14,132	13,606	28,448	26,621
Non-cash stock-based compensation	28	11	(9)	21
Operating income (loss)	14,617	11,057	28,005	24,936
Segment Assets
Cash, Cash equivalents, and Investments	60,598		60,598		43,125
Total current assets	112,845		112,845		91,497
Fixed assets, net	456,633		456,633		466,523
Goodwill	25,421		25,421		25,421
Total assets	656,414		656,414		647,228
Total current liabilities	71,627		71,627		77,644
Total debt	84,624		84,624		86,426
Capital Expenditures
Capital expenditures			19,929	23,692
International Telecom | Operating segments | Communication services
Revenue
Revenue	78,080	78,605	158,686	157,726
International Telecom | Operating segments | Mobility
Revenue
Revenue	19,062	21,007	39,198	41,402
International Telecom | Operating segments | Fixed
Revenue
Revenue	56,567	54,954	115,056	111,080
International Telecom | Operating segments | Carrier services
Revenue
Revenue	1,897	2,306	3,541	4,567
International Telecom | Operating segments | Other
Revenue
Revenue	554	338	891	677
International Telecom | Operating segments | Other
Revenue
Revenue	1,984	1,254	3,663	2,450
International Telecom | Operating segments | Managed Services
Revenue
Revenue	1,984	1,254	3,663	2,450
US Telecom | Operating segments
Revenue
Revenue	28,160	26,414	55,459	47,907
Depreciation and amortization	5,717	5,551	11,602	11,149
Operating income (loss)	1,826	1,521	4,019	(2,006)
Segment Assets
Cash, Cash equivalents, and Investments	29,304		29,304		38,240
Total current assets	58,928		58,928		54,207
Fixed assets, net	66,189		66,189		69,184
Goodwill	35,270		35,270		35,270
Total assets	222,046		222,046		222,356
Total current liabilities	23,994		23,994		24,905
Capital Expenditures
Capital expenditures			8,883	6,368
US Telecom | Operating segments | Communication services
Revenue
Revenue	28,160	26,414	55,459	47,907
US Telecom | Operating segments | Mobility
Revenue
Revenue	2,367	2,800	4,770	5,494
US Telecom | Operating segments | Fixed
Revenue
Revenue	4,937	3,622	9,762	5,581
US Telecom | Operating segments | Carrier services
Revenue
Revenue	20,856	19,992	40,927	36,832
Renewable Energy | Operating segments
Revenue
Revenue	874	1,448	2,196	2,938
Depreciation and amortization	486	638	1,100	1,253
Non-cash stock-based compensation	131		131
Operating income (loss)	(620)	167	(1,077)	(16)
Segment Assets
Cash, Cash equivalents, and Investments	22,801		22,801		25,054
Total current assets	25,537		25,537		27,534
Fixed assets, net	44,852		44,852		48,421
Total assets	71,033		71,033		76,723
Total current liabilities	1,164		1,164		$ 2,745
Capital Expenditures
Capital expenditures			1,634	817
Renewable Energy | Operating segments | Other
Revenue
Revenue	874	1,448	2,196	2,938
Renewable Energy | Operating segments | Renewable Energy
Revenue
Revenue	$ 874	$ 1,448	$ 2,196	$ 2,938